drivers/md/dm-core.h

   1 /*
   2  * Internal header file _only_ for device mapper core
   3  *
   4  * Copyright (C) 2016 Red Hat, Inc. All rights reserved.
   5  *
   6  * This file is released under the LGPL.
   7  */
   8
   9 #ifndef DM_CORE_INTERNAL_H
  10 #define DM_CORE_INTERNAL_H
  11
  12 #include <linux/kthread.h>
  13 #include <linux/ktime.h>
  14 #include <linux/blk-mq.h>
  15
  16 #include <trace/events/block.h>
  17
  18 #include "dm.h"
  19
  20 #define DM_RESERVED_MAX_IOS             1024
  21
  22 struct dm_kobject_holder {
  23         struct kobject kobj;
  24         struct completion completion;
  25 };
  26
  27 /*
  28  * DM core internal structure that used directly by dm.c and dm-rq.c
  29  * DM targets must _not_ deference a mapped_device to directly access its members!
  30  */
  31 struct mapped_device {
  32         struct mutex suspend_lock;
  33
  34         /*
  35          * The current mapping (struct dm_table *).
  36          * Use dm_get_live_table{_fast} or take suspend_lock for
  37          * dereference.
  38          */
  39         void __rcu *map;
  40
  41         struct list_head table_devices;
  42         struct mutex table_devices_lock;
  43
  44         unsigned long flags;
  45
  46         struct request_queue *queue;
  47         int numa_node_id;
  48
  49         enum dm_queue_mode type;
  50         /* Protect queue and type against concurrent access. */
  51         struct mutex type_lock;
  52
  53         atomic_t holders;
  54         atomic_t open_count;
  55
  56         struct dm_target *immutable_target;
  57         struct target_type *immutable_target_type;
  58
  59         struct gendisk *disk;
  60         struct dax_device *dax_dev;
  61         char name[16];
  62
  63         void *interface_ptr;
  64
  65         /*
  66          * A list of ios that arrived while we were suspended.
  67          */
  68         atomic_t pending[2];
  69         wait_queue_head_t wait;
  70         struct work_struct work;
  71         spinlock_t deferred_lock;
  72         struct bio_list deferred;
  73
  74         /*
  75          * Event handling.
  76          */
  77         wait_queue_head_t eventq;
  78         atomic_t event_nr;
  79         atomic_t uevent_seq;
  80         struct list_head uevent_list;
  81         spinlock_t uevent_lock; /* Protect access to uevent_list */
  82
  83         /* the number of internal suspends */
  84         unsigned internal_suspend_count;
  85
  86         /*
  87          * Processing queue (flush)
  88          */
  89         struct workqueue_struct *wq;
  90
  91         /*
  92          * io objects are allocated from here.
  93          */
  94         struct bio_set *io_bs;
  95         struct bio_set *bs;
  96
  97         /*
  98          * freeze/thaw support require holding onto a super block
  99          */
 100         struct super_block *frozen_sb;
 101
 102         /* forced geometry settings */
 103         struct hd_geometry geometry;
 104
 105         struct block_device *bdev;
 106
 107         /* kobject and completion */
 108         struct dm_kobject_holder kobj_holder;
 109
 110         /* zero-length flush that will be cloned and submitted to targets */
 111         struct bio flush_bio;
 112
 113         struct dm_stats stats;
 114
 115         struct kthread_worker kworker;
 116         struct task_struct *kworker_task;
 117
 118         /* for request-based merge heuristic in dm_request_fn() */
 119         unsigned seq_rq_merge_deadline_usecs;
 120         int last_rq_rw;
 121         sector_t last_rq_pos;
 122         ktime_t last_rq_start_time;
 123
 124         /* for blk-mq request-based DM support */
 125         struct blk_mq_tag_set *tag_set;
 126         bool use_blk_mq:1;
 127         bool init_tio_pdu:1;
 128
 129         struct srcu_struct io_barrier;
 130 };
 131
 132 int md_in_flight(struct mapped_device *md);
 133 void disable_write_same(struct mapped_device *md);
 134 void disable_write_zeroes(struct mapped_device *md);
 135
 136 static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj)
 137 {
 138         return &container_of(kobj, struct dm_kobject_holder, kobj)->completion;
 139 }
 140
 141 unsigned __dm_get_module_param(unsigned *module_param, unsigned def, unsigned max);
 142
 143 static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen)
 144 {
 145         return !maxlen || strlen(result) + 1 >= maxlen;
 146 }
 147
 148 extern atomic_t dm_global_event_nr;
 149 extern wait_queue_head_t dm_global_eventq;
 150 void dm_issue_global_event(void);
 151
 152 #endif